Formats messages according to very simple substitution rules. Substitutions can be made 1, 2 or more arguments.

For example,

MessageFormatter.format("Hi {}.", "there")

will return the string "Hi there.".

The {} pair is called the formatting anchor. It serves to designate the location where arguments need to be substituted within the message pattern.

In case your message contains the '{' or the '}' character, you do not have to do anything special unless the '}' character immediately follows '{'. For example,

MessageFormatter.format("Set {1,2,3} is not equal to {}.", "1,2");

will return the string "Set {1,2,3} is not equal to 1,2.".

If for whatever reason you need to place the string "{}" in the message without its formatting anchor meaning, then you need to escape the '{' character with '\', that is the backslash character. Only the '{' character should be escaped. There is no need to escape the '}' character. For example,

MessageFormatter.format("Set \\{} is not equal to {}.", "1,2");

will return the string "Set {} is not equal to 1,2.".

The escaping behavior just described can be overridden by escaping the escape character '\'. Calling

MessageFormatter.format("File name is C:\\\\{}.", "file.zip");

will return the string "File name is C:\file.zip".

The formatting conventions are different from those of MessageFormat which ships with the Java platform. This is justified by the fact that SLF4J's implementation is 10 times faster than that of MessageFormat. This local performance difference is both measurable and significant in the larger context of the complete logging processing chain.

See also format(String, Object), format(String, Object, Object) and arrayFormat(String, Object[]) methods for more details.

MessageFormatter.format("Hi {}.", "there");

MessageFormatter.format("Hi {}. My name is {}.", "Alice", "Bob");